The present invention relates to a process for the preparation of aryl trifluoromethyl ethers. More specifically, the present invention relates to such a process which comprises contacting a phenol with at least one perhalomethane and at least one fluorinating agent.
Aryl trifluoromethyl ethers are useful as intermediates for a variety of applications, including agricultural and pharmaceutical applications, functional and tribological systems, and polymers. Various reactions are known wherein aryl fluoromethyl ethers can be prepared from aryl halomethyl ethers with non-fluoro halo substituents. For example, U.S. Pat. 4,620,040 discloses a process for the preparation of aryl trifluoromethyl ethers in which a trichloroanisole is reacted with hydrogen fluoride in the presence of a fluorinated alumina catalyst. U.S. Pat. No. 4,600,787 discloses a two-step process for partially fluorinating perhalogenated anisoles with hydrogen fluoride or alkali metal fluorides, and then treating the partially-fluorinated anisoles with catalysts such as halides of boron, aluminum, tin, arsenic, antimony, titanium, molybdenum and iron.
U.S. Pat. No. 4,093,665 discloses a process for the fluorination of aryl perfluoroalkyl ethers using sulfur tetrafluoride in hydrogen fluoride solution. French Pat. No. 2,214,674 discloses a process for the fluorination of aryl chlorothioformates with molybdenum hexafluoride. U.S. Pat. No. 4,157,344 discloses a one-step process for the production of aryl trifluoromethyl ethers in which a phenolic compound is reacted with a perhalomethane in the presence of at least three molar equivalents of hydrogen fluoride.
The processes described above require a two-step process involving the production of aryl perhalogenated intermediate materials and/or require the use of harsh fluorinating agents such as hydrogen fluoride. It would be advantageous to provide a one-step process for the production of aryl trifluoromethyl ethers which does not require the use of hydrogen fluoride as a fluorinating agent.